Powder actuated tool



Sept. 25, 1962 L. w. BELL ETAL 3,055,008

POWDERACTUA'ITED TOOL Filed April 21, 1959 3 Sheets-Sheet 1 INVENTORS LEWIS WALTER BELL l WILLIAM A. EAGER @i BY RICHARD H. MAYNARD their ATTORNEYS V Sept. 25, 1962 w. BELL ETA].

POWDER ACTUATED TOOL 5 Sheets-Sheet 2 Filed April 21, 1959 I INVENTORS LEWIS WALTER BELL WILLIAM A. EAGER BY RICHARD H. MAYNARD EM7QZ Q their ATTORNEYS Sept. 25, 1962 L. w. BELL EI'AL POWDER ACTUATED TOOL 3 Sheets-Sheet 3 Filed April 21, 1959 INVENTORS LEWlS WALTER BELL WILLIAM A. EAGER BY RICHARD H. MAYNA FIG.

their arromvgrs Unite State 3,055,008 POWDER ACTUATED TOOL Lewis Walter Bell, Monroe, N.Y., William A. Eager,

Westwood, N.J., and Richard H. Maynard, Mountainviile, N.Y., assignors, by mesne assignments, to Star Expansion Industries Corporation, a corporation of Delaware Filed Apr. 21, 1959, Ser. No. 807,900 13 Claims. (Cl. 1-445) This invention relates to powdered devices for driving studs into masonry and the like and, more particularly, to a new and improved stud gun embodying special safety features.

A rapid and efiicient method of mounting a stud, such as a bolt or nail, in masonry structures is to drive the stud into the structure with an explosive charge. Stud guns for accomplishing this have been devised but they have been found to be hazardous in many respects, either as a result of misuse or because of unforeseen circumstances.

As an example, if a gun devised to embed a stud in a thick masonry wall is used against a wall that is too thin, the stud can pass completely through the wall and injure persons on the other side. In some cases, an attempt is made to avoid this result by providing a stud with a large heavy flange or thick washer, but this is undesirable in many instances because the flange or thick washer is permanently retained between the wall and the projecting portion of the stud.

Accordingly, it is an object of this invention to provide a new and improved stud gun having highly effective safety features.

Another object of the invention is to provide a stud gun arranged to prevent a stud from travelling more than a predetermined distance beyond the end of the gun.

A further object of the invention is to provide a gun of the above character capable of embedding a stud in masonry of any thickness and preventing travel beyond a predetermined point without interposing an arresting member between the stud and the masonry.

These and other objects of the invention are attained by providing a stud gun with a removable arresting member at the end of the gun barrel. This arresting member is arranged to permit a stud to emerge from the barrel but to prevent a stud carrying projectile from completely leaving the barrel. Preferably, the stud carrying projectile is longitudinally split to facilitate removal from the stud after it is embedded. In addition, locking means actuated by the arresting member may be included in the gun to prevent firing unless the arresting member is in pos1t1on.

Further objects and advantages of the invention will be apparent from a reading of the following description in conjunction with the accompanying drawings in which:

FIG. 1 is a view in longitudinal section illustrating one form of stud gun arranged according to the invention;

FIG. 2 is an end view of the gun shown in FIG. 1;

FIG. 3 is a sectional view taken on the lines 33 of FIG. 2 illustrating the stud gun after firing;

FIG. 4 is a sectional view similar to that of FIG. 3 showing a diiferent form of stud and projectile adapted for use with the stud gun;

FIGS. 5 and 6 illustrate extracting tools for removing studs from the gun in the event of a misfire;

FIG. 7 is a fragmentary view illustrating a form of stud gun having a trigger-actuated firing pin;

FIG. 8 shows the gun of FIG. 7 in the cocked condition;

FIG. 9 illustrates a modified projectile for use with the gun;

3,55,d8 Patented Sept. 25, 1962 ice FIG. 10 shows a stud adapted to be broken off after it is driven in; and

FIG. 11 is a view showing a modified barrel plug.

In the embodiment of the invention illustrated in FIGS. 1, 2 and 3, the stud gun comprises a barrel member 10 aflixed at one end to a base plate 11 as by welding, an aperture 12 in the base plate being aligned with the bore 13 of the barrel. A housing .14 surrounding the barrel extends around the edges of the base plate and two bolts 15 mounted in the base plate extend through openings 16 in the housing to maintain alignment and to permit relative longitudinal motion of the barrel and the housing.

Each bolt 15 is surrounded by a spring 17 extending from the base plate to the housing to urge the housing against the head of the bolt while, as shown in FIG. 3, the housing also carries two spacing bolts 18 which are adjustable to limit the motion of the base plate and the barrel with respect to the housing. The ends of these bolts are normally spaced from the base plate 11 except when the gun is in the cocked condition, as illustrated in FIG. 3.

According to the invention, FIG. 1 shows that a recess 19 is cut into the base plate 11 adjacent the aperture 12 to receive a projectile arresting member, such as a metal ring 2b, which overlaps the end of the opening 12. As described more fully hereinafter, the ring 20 has an opening Zita and the size of this opening is selected to permit a stud to pass through but to block a stud carrying projectile from passing out of the bore 13. In order to hold the arresting member 20 in position when the gun is fired, two scissor plates 21 and 22 are pivotally mounted on studs 23 and 24 in the base plate 11 for angular motion toward and away from the axis of the bore 13. Two scissor plate guides 25 and 26 mounted at opposite ends of the base plate 11, as by bolts 27, have recesses 28 adjacent to the base plate and each of the scissor plates 21 and 22 includes tongue portions 29 at opposite ends which fit into the recesses 28. As a result, the scissor plates 21 and 22 are held securely in place against the base plate 11 and are movable between an open position, illustrated in FIG. 2, which permits the arresting ring 20 to be inserted, and a closed position, shown in FIG. 3, covering the outer portions of the arresting member but leaving the opening Zita unobstructed.

A compression spring 3i) is positioned between the two scissor plates 21 and 22 urging them toward the open position. However, two cam members 31 and 32 mounted in the housing 14, as shown in FIGS. 2 and 3, are shaped to drive the scissor plates inwardly toward the closed position when the housing 14- is moved longitudinally with respect to the base plate 11 and the barrel 10 toward the cocked position shown in FIG. 3.

As described in detail below, the longitudinal relation between the barrel 10 and the firing mechanism of the gun is arranged so that the gun cannot be fired unless the housing 14 has been moved to the cocked position shown in FIG. 3, compressing the springs 17. In order to make certain that the gun cannot be cocked in this manner unless the arresting member 28 is in position in the recess 19, the forward end of the barrel 10 carries a pivotally mounted latch lever 33. One end 34 of the lever is movable into and out of the recess 19 in response to pivoting motion of the lever while the other end is formed with a notch 35. This notch is aligned with a shoulder 36 on the housing 14 when theend 34 is in the recess 19 and is displaced from the shoulder when the end 34 is outside the recess. Therefore, by virtue of a spring 37 urging the end 34 toward the recess 19, unless there is an arrest: ing member 20 in position in the recess, the housing 14 is prevented from moving toward the cooked position by engagement of the notch 35 and the shoulder 36.

At its -other end, the barrel 10 has a plug 38 formed with a bore 39 coaxial with the bore 13 and small enough to block the head of a cartridge 40. Inasmuch as the cartridge 40 is blown against the adjacent portion of the plug 38 when the gun is fired, it may tend to spread out and become wedged in the bore 13. To obviate this, a plug 38a, shown in FIG. 11, having a spherically concave surface 3812 next to the projectile position may be used. With this plug the cartridge tends to be deformed into a spherical shape rather than flattening out and therefore will not be wedged into the bore 13. A firing pin 4i. slidably supported in the bore 39 has a narrow firing tip 42 at one end and passes through an opening 43 in the hous ing 14, a head 44 being mounted on the pin at the outer end. Also, a spring 45 is positioned between the head 44 and the housing to urge the tip 42 away from the inner end of the plug 38 while a flange 46 limits the motion of the firing pin in this idirection. A sleeve 44a, which may or may not be attached to the head 44, surrounds the adjacent portion of the spring 45 and limits the motion of the head in the direction of the housing 14.

In order to prevent firing of the gun unless the housing 14 has been moved forwardly to the cocked position, as shown in FIG. 3, the length of the firing pin is selected so that with the barrel held in the forward position by the latch lever 33 the tip 42 cannot come into contact with a cartridge 40 at the inner end of the plug 38 even though the firing pin head 44 is driven toward the housing 14 as far as the sleeve 44a which surrounds the spring, will permit. On the other hand, the firing pin is long enough so that when the head 44 is depressed, with the housing 14 in the cocked position, the tip 42 can come into contact with a cartridge at the inner end of the plug 38, when the head of the firing pin is struck.

Preferably, the cartridge 40 is supported in a blind hole 47 at the rear of a projectile 48, the projectile being suitably arranged to receive a stud 49 at its forward end. If desired, a projectile 48a of the type illustrated in FIG. 9 may be used with the gun. This projectile includes a threaded axial passageway extending between the forward portion and the hole 47 and a set screw 48b is normally retained in this passageway. If a cartridge 40 misfires, the screw 48b can be driven to the right as viewed in FIG. 9 to remove the cartridge so that no prying action against the cartridge flange is necessary. On the other hand, inasmuch as the cartridge 40 is normally retained in the hole 47 only by friction, when the cartridge explodes it is driven out of the hole 47 as the projectile moves forward and is therefore self-ejecting.

The diameter of the projectile 48 approximates that of the bore 13 of the barrel and one or more spring rings 50 are supported in grooves in the periphery of the projectile body. These rings are fabricated of resilient material, such as spring steel, and they form a tight fit within the bore 13 So that once a projectile 48 is loaded in the barrel it is retained firmly in position against the inner end of the plug 38 regardless of the orientation of the stud gun. A spring loaded detent 549a may be installed in the side of the barrel to assist in retaining the projectile snugly against the plug 38 by engagement in a groove 50b.

At its forward end, the projectile 48 is provided with a portion 51 of reduced diameter having an axial length "approximately equal to the combined thickness of a scissor plate 21 or 22 and the arresting member 20, and the opening 20a of the arresting member has a diameter large enough to permit this portion of the projectile to pass through while preventing passage of the full diameter portion. In addition, the material of the arresting member 20 is preferably softer than that of the projectile so that the projectile is not deformed upon impact, while the arresting member undergoes some distortion to absorb the shock of the impact when insuflicient resistance to penetration is encountered. For example, the arresting member may be made of aluminum or zinc alloy while the projectile is of steel.

In order to facilitate the rapid mounting and removal of the stud 49 from the projectile 48 and to accommodate various forms of stud, the stud-holding forward end of the projectile is preferably split longitudinally to provide a removable section 52, as best seen in FIG. 3. Inasmuch as this removable section includes a substantial area within the full diameter portion of the projectile, it will be apparent that the two parts of the projectile are held securely together as long as the projectile assembled with the stud is within the bore of the barrel. The interior of the projectile along the dividing line of the two portions is formed in an appropriate manner to receive the end of the stud. In the example shown in FIG. 1, the end of the stud 49 is formed as a bolt and the projectile has a correspondingly threaded interior 53 to retain this stud. As illustrated in FIG. 10, a stud 49a having a groove 4% at the junction betwen the threaded portion and the forward portion may be used if no permanent projection is necessary. In this case the threaded portion can be broken off after the stud is driven in. Also, in order to prevent spalling of the work surface when the stud is driven into masonry or the like, a small washer 54 may be force-fitted to the forward end of the stud shank.

In operation, a stud 49 is mounted in the projectile 48 by removing the section 52", inserting the head of the stud, and replacing the removable section. A blank cartridge 4% is inserted in the hole 47 at the opposite end and the projectiie is pushed into the bore 13 until the end of the projectile is seated against the inner end of the plug 38. Frictional contact of the rings 513 with the bore 13, and the seating of the detent 50a in the groove Sub retain the .projectile in this position. In this condition, the gun cannot be fired by actuation of the firing pin because the barrel It) is in the forward position. Moreover the barrel cannot be pushed back to the cocked position because the latch lever 33 is blocked by the shoulder 36.

In order to permit cocking, an arresting member 20 is inserted in the recess 19 thus holding the latch 33 in the inactive position shown in FIG. 1. The two scissor plate guides 25 and 26 are then placed against the object into which the stud is to be embedded and the housing 14 is urged toward the object against the pressure of the springs 17. As the housing moves with respect to the base plate 11, the cam members 31 and 32 drive the scissor plates 21 and 22 inwardly over the outer edges of the arresting member 20 to hold it in place. At the same time, the firing pin 41 moves toward the barrel 1%) and when the spacing bolts 18 stop the relative forward motion of the housing with respect to the barrel, the tip of the firing pin is far enough forward to be within the reach of the cartridge 4i).

Firing is accomplished by driving the firing pin against the cartridge rapidly, as by a hammer blow on the head 44. The resulting explosion drives the projectile 48 to the forward end of the barrel forcing the pointed end of the stud 49 into a concrete formation 55, for example, while the washer 54 is retained against the surface of the formation, as illustrated in FIG. 3, to hold the surrounding material in place. The stud 49 and the smaller diameter forward portion 51 of the projectile 48 pass freely through the opening 20a of the arresting member 20 but when the stud has become fully embedded in the object 55, the full diameter portion of the projectile 48 normally stops short of the arresting member 20. If insuflicient resistance to penetration is met by the stud 49 the full diameter portion of the projectile 48 strikes the arresting member 20 and the projectile is brought to a stop, the arresting member being held in place by the scissor plates 21 and 22. Even if the explosion of the cartridge has generated sufficient force to drive the stud and projectile farther into or through the object 55, this force is absorbed by the arresting member, which may be deformed slightly, so that further motion of the stud and projectile is effectively prevented. In this manner, the stud is embedded to no more than the desired depth and is prevented from passing through the object regardless of its strength or thickness.

As the stud gun is withdrawn from the object, the springs 17 urge the base plate 11 away from the housing and the cam members 31 and 32 permit the scissor plates 21 and 22 to move to the open position under the influ ence of the spring 30. Continued withdrawal of the gun from the object causes the projectile 48 to be pulled out of the barrel 1% which action removes arresting member 20 from recess 19. The arresting member 20 is then moved toward the forward end of the projectile 48 to release the removable section 52 and, with this section out of the way, the projectile is free to be withdrawn from the head of the stud.

In the event of a misfire, the stud and projectile can be withdrawn from the barrel 1!) by inserting an extracting tool of the type shown in FIG. 5 or FIG. 6. The extractor 56, illustrated in FIG. 5, has a pair of spring biased jaws 57 and 58 arranged to snap over the washer 54 of the stud 49 when the tool is inserted in the bore so that the stud and projectile can be removed by withdrawing the tool. To permit this engagement, the tips 59 and 60 of the jaws 57 and 58 are sloped inwardly so that the jaws can open and pass over the washer 54 within the confines of the bore 13. Similarly, the extractor 61 shown in FIG. 6 has a recessed head 62 shaped to fit around the washer 54 while within the bore 13, and a spring pressed catch 63 has an inwardly inclined head arranged to slide over the washer so that the stud can be extracted by withdrawing the tool from the bore. If desired, a ramrod 64 may be formed at the opposite end of either form of extractor, or as a separate tool to push the stud and projectile into place in the bore.

A projectile adapted for use with the stud gun may also be shaped to receive a nail-type stud 65 in the manner illustrated in PEG. 4. In the illustrated example, the nail 65 is of the double-headed type having an inner head 66 and an outer head 67 with an optional breakoff groove 66a above and adjacent to the inner head. The split portion of the projectile 48' is recessed to receive the outer head and grip the shank between the outer and inner heads. This form of stud may be used to mount a wooden block 68 to a concrete object 55 for example, and if no permanent projecting head is desired, the outer head 67 may be broken off after the stud is embedded.

In the embodiment shown in FIGS. 7 and 8, a triggeractuated firing pin is provided to eliminate the necessity of applying a hammer blow. In this case, the housing 14' is formed with a pistol grip 69 and a spring-biased trigger 70 is pivotally supported on the housing. A firing pin 71 having a flange 72 passes through an opening 73 in the housing and a strong compression spring 74 extends from the flange to the housing. In addition, a stop member 75 mounted in the housing intercepts the flange 72 to limit the forward motion of the firing pin 71. The stop member 75 is positioned with respect to the barrel of the gun to prevent the firing pin 71 from contacting a cartridge in the projectile 48 when the projectile is against the inner end of the plug 38 and the barrel 10 is in the forward position, as shown in FIG. 7. When the barrel is in the cocked position illustrated in FIG. 8, the stop member 75 no longer prevents the forward end of the firing pin from contacting the cartridge in the projectile.

Pivotally mounted at the rear end of the barrel 10, a sear 76 is shaped with an arm 77 extending toward the location of the trigger 78 and a dog 78 mounted on this arm is positioned between two rigid guard plates 79 and 80 which normally prevent motion of the arm 77 and pivoting of the sear 76. One of these plates, the sear guard 79, is mounted on the housing 14' and includes an opening 81 located to permit pivoting of the sear 76 only when the barrel 10 is in the rear or cocked position. The other plate 80, called the trigger guard, normally prevents the operating arm 82 of the trigger 70 from mov- 6 ing toward the sear arm 77 but has an aperture 83 permitting the trigger arm 82 to strike the dog 78 when the barrel 10 is in its cocked position. As a result of this arrangement, accidental discharge of the gun, as by jarring of the sear 76, is effectively prevented.

Adjacent to the firing pin 71, the sear 76 carries a pivotally mounted cocking member 84 biased by a spring 85. This member normally lies next to the flange 72, as illustrated in the drawings, and is urged toward that position by the spring 85 but it can be pivoted outwardly toward the pistol grip 69 when the barrel 10 is moved to the forward position after the firing pin has been released.

In operation, the various elements of the trigger-actuated stud gun are normally in the position shown in FIG. 7 so that the sear 76 is held in place by the sear guard 79. Consequently, the gun cannot be operated until the forward end has been pressed against an object in the manner described above to cock the gun. When the housing 14 has been moved forwardly to the cocked position shown in FIG. 8, the aperture 83 is aligned with the trigger arm 82, permitting it to actuate the sear dog 78 while the opening 81 in the sear guard 79 is in a position to permit the dog to be driven toward the barrel 10. Moreover, the forward motion of the housing while the firing pin '71 is held back by the sear 76 and the cocking member 84 has compressed the spring 74 to cock the tool.

When the trigger 70 is operated, the dog 78 moves into the opening 81 pivoting the sear 76 to release the firing pin flange 72 from the cocking member 84 and the spring 74 drives the firing pin against the cartridge in the projectile 48. As the trigger 70 is released and the barrel 10 is restored to its forward position, the dog 78 is forced out of the opening 81 by virtue of a bevelled edge, pivoting the sear 76. At the same time, the cocking member 84- turns outwardly toward the pistol grip 69 because of its contact with the spring 74 or the side of the firing pin 71 and this permits the sear 76 to return to its normal position. After the barrel 18 has moved all the way forward, the cocking member 84 passes over the flange 72 and the spring 85 pulls it back to its operating position illustrated in FIGS. 7 and 8.

-It will be readily apparent that the stud gun described above provides a novel and efficient device for embedding studs in any object while completely eliminating the hazards formerly encountered in the use of such guns. Moreover, an operator is effectively prevented from disabling the safety features while using the gun.

Although the invention has been described herein with reference to specific embodiments, many modifications and variations therein will readily occur to those skilled in the art. For example, the rear portion of the housing 14 may be hinged to the forward portion to swing open and permit breech loading of the gun. In this case, the plug 38 should be easily removable from the barrel so that the projectile can be inserted from the rear. Accordingly, all such variations and modifications are included within the intended scope of the invention as defined by the following claims.

We claim:

1. A drivable unit for driving a fastener through a bore into an object comprising a piston slidable in the bore having a forward portion adapted to receive a fastener and provided with a hole at the opposite end adapted to receive a cartridge freely so that the cartridge is selfejecting when fired including a passageway between the hole and the forward portion and a member in the passageway adapted to be driven into the hole to remove a cartridge.

2. Apparatus for driving a fastener into an object comprising a piston adapted to receive at one end a fas' tener having a smaller diameter than the piston, barrel means having a bore and a forward end for directing the piston and a fastener mounted therein toward the object, piston arresting means comprising an impact-absorbing member capable of being deformed to absorb the energy of the piston supported at the forward end of the barrel means and projecting inwardly toward the axis of the barrel means far enough to intercept the piston but not far enough to prevent the fastener from passing out of the barrel means, and releasable holding means mounted at the forward end of the barrel means and movable in a transverse direction with respect to the barrel axis between an inner position retaining the impact-absorbing member in place at the forward end of the barrel means and an outer position permitting removal of the impactabsorbing member from the forward end of the barrel means.

3. Apparatus for driving a fastener into an object comprising a piston adapted to receive at one end a fastener having a smaller diameter than the piston, barrel means having a bore and a forward end for directing the piston and a fastener mounted therein toward the object, piston arresting means comprising an arresting member supported at the forward end of the barrel means and projecting inwardly toward the axis of the barrel means far enough to intercept the piston but not far enough to prevent the fastener from passing out of the barrel means, releasable holding means mounted at the forward end of the barrel means and movable in a transverse direction with respect to the barrel axis between an inner position retaining the piston arresting member in place at the forward end of the barrel means and an outer position permitting removal of the piston arresting member from the forward end of the barrel means, a housing surrounding the barrel means and longitudinally movable with respect thereto between a forward position and a rearward position, and means linking the housing and the holding means to move the holding means to the inner position when the housing is moved to the forward position and to the outer position when the housing is moved to the rearward position.

4. Apparatus according to claim 3 including locking means linking the barrel means and the housing to prevent motion of the housing to the forward position and release means for the locking means including a detector responsive to the presence of the piston arresting member at the forward end of the barrel means to release the locking means and permit relative motion of the housing and barrel means when the piston arresting member is in position at the forward end of the barrel means.

5. Apparatus according to claim 3 wherein the barrel has a breech end within the housing and including means associated with the housing for firing an explosive cartridge located in the breech end of the barrel, said firing means being movable with the housing form a rearward safety position with respect to the barrel means when the housing is in its rearward position to a forward firing position with respect to the barrel means when the housing is in its forward position.

6. Apparatus according to claim 5 wherein the firing means comprises a firing pin supported in the housing for limited motion with respect thereto toward and away from the breech end of the barrel means and having a length short enough to prevent contact with an explosive cartridge in the breech end of the barrel means when the housing is in its rearward position but long enough to permit contact with an explosive cartridge when the housing is in its forward position.

7. Apparatus according to claim 6 including movable sear means mounted on the barrel means and normally positioned to intercept the firing pin as the housing is moved forwardly with respect to the barrel means,,sear guard means mounted on the housing and positioned to prevent motion of the sear means away from the firing pin intercepting position except when the housing is in its forward position, and trigger means movably mounted on the housing in a location to engage the sear means when the housing is in the forward position.

8. Apparatus according to claim 7 including trigger guard means mounted on the barrel means and positioned with respect to the trigger means to prevent operation thereof except when the housing is in the forward position.

9. In combination, a drivable unit for driving a fastener into an object comprising a piston having a full diameter portion and a forward portion of reduced diameter and longitudinally split into at least two separate sections to receive the head of a fastener, each section including part of the full diameter portion, barrel means having a bore to receive the piston with a bore diameter approximating that of the full diameter piston portion to retain the two sections together when the piston is in the bore and to direct the piston and fastener toward the object, and arresting means mounted at a forward end of the barrel means and projecting toward the axis of the barrel means far enough to intercept the full diameter piston portion, but not far enough to intercept the reduced diam eter piston portion.

10. The combination according to claim 9 including friction means mounted on the full diameter piston portion forming a tight fit with the bore of the barrel means to hold the piston in position in the bore.

11. A drivable unit for driving a fastener through a bore into an object comprising a piston which is longitudinally split into at least two separate sections from one end over at least a portion of its length and having a diameter in at least part of the split portion which is approximately the same as the diameter of the bore, the separate sections being formed at said one end with an axial opening to receive the head of a fastener.

12. A drivable unit according to claim 11 wherein the piston sections are formed with recesses within the hole to retain a complementary shaped head of a fastener.

13. A drivable unit according to claim 11 wherein the piston sections are formed with internal threads within the hole to retain a fastener having a threaded head.

References Cited in the file of this patent UNITED STATES PATENTS 46,220 De Witzloben Feb. 7, 1865 2,064,503 Temple Dec. 15, 1936 2,632,890 Tietig Mar. 31, 1953 2,663,259 Catlin et al Dec. 22, 1953 2,724,116 Termet Nov. 22, 1955 2,747,187 Catlin et a1 May 29, 1956 2,767,398 Pfaff Oct. 23, 1956 2,770,988 Jasse Nov. 20, 1956 2,895,135 Hilti July 21, 1959 2,904,787 De Caro Sept. 22, 1959 2,923,940 Kvavle Feb. 9, 1960 2,925,602 Kopf et al Feb. 23, 1960 FOREIGN PATENTS 62,135 France Dec. 29, 1954 166,735 Australia Jan. 31, 1956 167,800 Australia June 6, 1956 744,822 Great Britain Feb. 15, 1956 986,345 France Mar. 21, 1951 1,031,736 Germany June 4, 1958 

